19 January 2008

Obviously the nature vs. nurture debate is not clear-cut. It is going to be some sort of balance between the two, this is not really in question, rather were on the continuum between genes and environment does the end point lie? As I mentioned in,“Nature vs. Nurture – A Short Introduction:”, the prelude/introduction to this article historically there have been trends, first starting with a genetic emphasis in the 1800’s and then moving more to an environment based approach in the mid 1900’s. I like to think of it as rather like a pendulum swinging. Its gone from one extreme to the other and now gravity (which I suppose in our metaphor would be scientific research) is slowly doing its thing and bringing it closer to the middle. I’m sure most people would agree with me up to here, this all seems rather self-evident. However then you must realise that certain things about us seem to be more genetically determined, and other more environmentally determined. To keep with our previous allegory we must now imagine a pendulum for every characteristic, both physical and psychological for each human being. Suddenly we have a large amount of pendulums!

Take a characteristic like eye colour and you can see that genetics seem to play by far the larger role in this instance. Once you are born with a certain eye colour, seldom do they change. In contrast while some people may build muscle better than others it is possible for all individuals to increase their lean muscle weight with the correct training and decent nutrition. In fact many people with not so great muscle building genetics can still become much more muscular than their genetically superior counterparts who don’t exercise. Arnold Schwarzenegger provides yet another example of environmental influences. While Arnold was always quite ripped in his youth he is now a middle aged pudgy governor of California, who has no doubt gained the pounds as he is no longer dieting as he once was, nor exercising to the same extreme. This information should be seen as an empowering thing though. Think about it for a minute. This is Schwarzenegger! If he has genes which allow him to get fat like anyone else than it also shows than anyone else can lose fat and look to a degree (within reason and everything) like he did! It works both ways. You see Schwarzenegger probably does have good genetics for that sort of thing (and a large amount of steroids) but that doesn’t mean that he can just sit on his arse all day. By the same token you may have quite bad genetics for something like muscle building or fat loss, but that by NO means whatsoever condemns you to a life of being obese. Psychologically if you use the excuse that your genes are crap then you’ve given up before you’ve even started.

Feel empowered by the fact that ultimately it is that environmental influence which tweaks what genes we have. Your friend might lose fat twice as easily as you. But if he never exercises then he won’t be realising his potential, whereas you can. Genetics are a bit like getting good cards in a card game I guess. It helps, but it doesn’t guarantee success. Ultimately it comes down to how you play the game, and that is an environmental thing. Having said that this is only with regards to body fat and muscle and so forth. Many other characteristics like the aforementioned eye colour are far more set in stone. Height is similar in that each person has a potential maximum height which is largely genetically based. Certainly environmental factors like malnutrition can limit someone’s potential, but the fact is if all your relatives are really short, chances are you will be as well. Hence height should be seen as a predominantly genetic characteristic. Tweaking the pituitary gland to release more human growth hormone could I suppose theoretically lead to increased height, and perhaps drugs and so on could do this, but it would be incredibly hard to alter ones height once it was set short of taking very new drugs which alter our biochemistry, essentially altering our genes.

This brings me to a rather interesting point. At what point in time do genes and the environment mesh into one larger category? In my previous article “Exercising Efficiently – the Intensity Debate:” I compared two different groups of mice who had been genetically altered. One group known as “Marathon Mice” could run much further than their counterparts, had far more slow-twitch muscle and had a great ability to not gain weight. Interestingly scientists are now saying that if you are already born your genes might be set, but you can still take drugs to do the same tweaking. Hence scientists are in the process of inventing a pill which does exercise for us. Basically the pill tweaks a gene called PPAR-d (delta) by turning it on, so that the body wastes excess energy.Here’s a link for anyone interested:http://www.sciencedaily.com/releases/2007/04/070429154936.htm

Essentially my question is what happens when environmental influences (crazy scientists) are able to tweak genetics, after our genes are set? Is this an environmental influence or a genetic influence? Surely it is both. Here the line between the two categories blurs all the further. Interestingly, in the case of the “marathon mice” those who were given a pill to alter PPAR-d, only gained the fat burning effects and not the increased endurance. This does indicate that perhaps there are limits to what can be changed after our genes have been set.

Another interesting issue could be to do with the ethics behind fiddling with genetics. Doesn’t changing our genetics effectively change who we are? After our DNA code is unique to us (with the exception of identical twins). The nature vs. nurture debate is certainly an interesting one. It is also one which may in the greater scheme of things be unanswerable in a simple this or that manner. The issues we are dealing with are complex, and hence the answer too will reflect this. My understanding is that different characteristics are determined to differing degrees by both the environment and ones genetics. What we must remember is that while we cannot change our genetics (at least not at this point in time) we should not dwell on that we cannot control, but rather be empowered by what is in our control. We must take responsibility for our environmental influences, and alter them as we see fit to create an environment we find hospitable for our general wellbeing.

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About Me

Medical student, who is constantly forgetting all the many abstracts and science articles he's read eons ago, and as such thought he'd compile a blog of interesting recent scientific developments and hash-tag them so he can go back and quickly re-find information. He finds all of this stuff very interesting, maybe you will too?